This invention relates to method and apparatus and to a system for applying heat shrink film to containers and other articles.
More particularly, this invention relates to applying heat shrink film to cylindrical containers although, as will appear, the invention is also applicable to applying heat shrink film to containers which are not cylindrical in shape and to articles other than containers.
Heretofore apparatus and a method have been provided for applying heat shrink film to cylindrical containers by a series of steps as follows.
1. Heat shrink film is formed into a tube slightly larger in diameter than the container to which it is to be applied.
2. The container is preheated or, if the film application is carried on in conjunction with the manufacture of glass containers, the glass containers can be taken from the glass manufacturing operation while they are still hot or warm.
3. The cylindrical sleeve is placed over the container.
4. The sleeve is then heated to shrink it onto the container.
This procedure is elaborate and expensive. Among its disadvantages are the following.
The film material must be preformed into a cylinder rather than being applied directly from a roll of film material to the containers.
The preformed sleeves, since they are larger in diameter than the containers, must be shrunk in their entirety. This requires more heat for shrinking, both because the entire material of the sleeve must be heat shrunk and because the containers themselves must be heated.
Representative of the method and system referred to above is U.S. Pat. No. 3,822,459, issued Jul. 9, 1974, to Stephen W. Amberg et al, and assigned to Owens-Illinois, Inc.